Groundwater Impacts of Water Consumption Patterns in Bengaluru, India

Abstract

While growing urban demand has the potential to significantly impact the water resources of distant sources, there is no doubt that it drastically modifies the local water balance. Despite this, very little research has emerged on the natural and modified water balance of urban areas in India. In this paper, taking Bangalore as a case study, we illustrate the possible impacts of domestic water supply and consumption through lumped and distributed simulations of net groundwater recharge. Our lumped model results show that a severe lack of systematic data on actual groundwater extraction drives large uncertainty in the direction and magnitude of net recharge change on a city-wide scale. Distributed groundwater modeling of the impacts of groundwater extraction shows that net recharge in the centre of the city has likely caused an increase in groundwater tables over time, driven by leakage through water supply and sewerage pipes. However, around the centre of the city, domestic water extraction seemed to show less impact on net groundwater recharge. It is possible though that higher industrial sector pumping in the outer areas of the city might drive water tables deeper in those areas. We conclude with recommendations for gaining a better understanding of Bangalore’s groundwater status and dynamics, as well as the importance of systematic collection of water extraction data from all sectors, and from all sources.